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- Question
Which two atoms form an ionic bond?
- Correct Answer
- Ionic bonding is a type of chemical bond in which valence electrons are lost from one atom and gained by another This bond generates two oppositely charged ions In ionic bonds, the metal loses electrons to become a positively charged cation, whereas the nonmetal accepts those electrons to become a negatively charged anion Example :: One example of an ionic bond is the formation of sodium fluoride, NaF, from a sodium atom and a fluorine atom In this reaction, the sodium atom loses its single valence electron to the fluorine atom, which has just enough space to accept it The ions produced are oppositely charged and are attracted to one another due to electrostatic forces
- 1. In a compound, chemical energy is contained in the
Options- A. bonds
- B. movement of the electrons
- C. unbonded electrons
- D. nuclei of the atoms Discuss
- 2. What is the oxidation number of carbon in NaHCO3?
Options- A. -4
- B. -3
- C. +4
- D. +2 Discuss
- 3. Nucleic acids are polymers of
Options- A. Nucleotides
- B. Aminoacids
- C. Proteins
- D. Sugars Discuss
- 4. Under which conditions are gases most soluble in water?
Options- A. low pressure and low temperature
- B. low pressure and high temperature
- C. high pressure and low temperature
- D. high pressure and high temperature Discuss
- 5. Covalent bonds hold atoms together because they
Options- A. fill shells without giving atoms much charge
- B. bring electrons closer to protons
- C. Both A & B
- D. use forces between nuclei as well as forces between electrons Discuss
- 6. Which statement about weak bonds is correct?
Options- A. Covalent bonds are weak bonds
- B. They are hard to break
- C. Weak bonds are transient and easily reversible.
- D. All of the above Discuss
- 7. Which statement about electrons and atomic orbitals is NOT true?
Options- A. An orbital can contain a minimum of two electrons
- B. An electron has the same amount of energy in all orbitals
- C. An atom?s lowest energy level has only two orbitals
- D. All of the above Discuss
- 8. Which half reaction correctly represents reduction?
Options- A. Fe2+ + e- ---> Fe3+
- B. Au3+ + 3e? ---> Au
- C. Ag ---> Ag+ + e-
- D. All of the above Discuss
- 9. Anaerobic glycolysis occurs without
Options- A. water
- B. glucose
- C. oxygen
- D. All of the above Discuss
- 10. What is the main ingredient in face powder?
Options- A. Calcium carbonate
- B. Talc
- C. Magnesium carbonate
- D. China clay Discuss
Chemistry problems
Search Results
Correct Answer: bonds
Explanation:
chemical energy is contained in the chemical bonds between the reactants in the chemical compounds.
Correct Answer: +4
Explanation:
The given compound is NaHCO3 Sodium bicarbonate which is commonly known as Baking soda.
Oxidation numbers are the charges on ions. When a neutral atom loses electrons it becomes positively charged. When a neutral atom gains electrons it becomes negatively charged.
Here the C represents the oxidation state of carbon in this compound. Compounds are electrically neutral, which is why we set the sum of the oxidation states equal to zero.
Sodium has a +1 oxidation state. Hydrogen has a +1 oxidation state. Oxygen has a -2 oxidation state. There are three oxygen atoms, which means the total oxidation state provided by both oxygen ions is -6. Adding up these oxidation states we get:
1 + 1 + (-6) + C = 0
-4 + C = 0
=> C = 4
This means the oxidation state of carbon in this compound is +4.
Correct Answer: Nucleotides
Explanation:
Nucleic acids are polymers of individual nucleotide monomers.
Each nucleotide is composed of three parts:
a 5-carbon sugar,
a phosphate group, and
a nitrogenous base.
Correct Answer: high pressure and low temperature
Explanation:
Henry's Law tells that the solubility of a gas is directly proportional to the partial pressure of the gas above the solvent. Hence under high pressure, more gas is dissolved.
Also that Henry's Law involves a constant which is temperature-dependent. Under high temperatures, less gas is dissolved whereas under low temperatures, more gas is dissolved.
For Example ::
You can think of a can of soda. The contents are under pressure and if you shake the can before opening, the soda fizzes out all over as you open it. So the higher the pressure, the more gas or more CO2 can be dissolved in the drink.
Eliminate choices 1 and 2. Now focus on the temperature. Soda goes flat (loses carbonation or gas) as it warms up. Soda is usually served cold because more of the carbonation or CO2 stays in the drink when the soda is cold.
Hence, in high pressure and low temperature conditions gases are most soluble in water.
Correct Answer: Both A & B
Explanation:
Covalent bonds hold atoms together because the attraction between the positively charged nuclei and the negatively charged shared electrons is greater than the repulsions between the nuclei themselves.
Correct Answer: Weak bonds are transient and easily reversible.
Explanation:
In chemistry, Weak bonds are those forces of attraction that, do not take a large amount of energy to break.
For example, hydrogen bonds are broken by energies in the order of 4 - 5 kcal/mol.
Ionic bonds, hydrogen bonds and van der Waals interactions are considered weak bonds.
Weak bonds are transient and easily reversible.
Correct Answer: All of the above
Explanation:
Yes, all the given statements are NOT true about electrons and atomic orbitals.
True statements are ::
An orbital can contain a maximum of two electrons.
An atom?s lowest energy level has only one orbital.
An electron has different amount of energies in all orbitals.
Correct Answer: Au3+ + 3e? ---> Au
Explanation:
A half reaction is either the oxidation or reduction reaction component of a redox reaction. A half reaction is obtained by considering the change in oxidation states of individual substances involved in the redox reaction.
Correct Answer: oxygen
Explanation:
Anaerobic glycolysis is the transformation of glucose to lactate when limited amounts of oxygen (O2) are available.
Hence, Anaerobic glycolysis occurs without oxygen.
Correct Answer: Talc
Explanation:
Talc or talcum is a clay mineral composed of hydrated magnesium silicate with the chemical formula H2Mg3(SiO3)4 is the main ingredient in face powders that absorbs moisture and oil.
It is also called as French Chalk. Other ingredients include Calcium carbonate (chalk), Magnesium carbonate, China clay, starches like rice and potato, zinc oxide,...
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